Mean pulsation rate = ______ (Control)

2. Place two of the animals in 75% seawater, two in 50% seawater, and two in 25% seawater. Allow the animals to settle and record an initial pulsation rate at (time 0 ). Wait fifteen

minutes and again record pulsation rate at (time 15 ).

3. Return each animal to normal seawater and again record pulsation rates after another

fifteen-minute interval at (time 30 ).

Salinity (% seawater)

Time Cassiopea

25% 1 time 0 2 mean 1

time 15 2

Station 2. Mangrove water quality; Cassiopea behavior and population density. At this station, students will measure pH salinity, temperature, dissolved oxygen, nitrates, and phosphates of the water at different sites in the mangrove. They will also observe normal populations of Cassiopea while snorkeling. [Work from a boat.]

1. Collect water samples at three points along a transect across a small mangrove lagoon. Take all samples from a depth of 0.5 m. Label bottles and store in cool box for analysis during the evening lab. Measure temperature at 0.5 m at each site.

Site 3 Temperature pH Salinity Dissolved O 2 Nitrates Phosphates

Site 1

Site 2

Describe each site (e.g, depth, turbidity, SAVs, wave energy, etc.): Site 1: __________________________________________________________________________

Site 2: __________________________________________________________________________ Site 3: __________________________________________________________________________

2. Estimate the population density of Cassiopea (number/rn 2 ) at the three sites. Place a 0.25 m 2 quadrat on the bottom. Count the number of Cassiopea that occur completely or in part within the quadrat. Do not count animals that just touch the outside edge of the quadrat. Repeat three times.

Number of Cassiopea

Quadrat

Site 1

Site 2

Site 3 1

Station 3. Water quality in mangrove, seagrass, and coral-reef communities. At this station, students measure pH salinity, temperature, dissolved oxygen, nitrates, and phosphates of the water at three sites from mangrove, to seagrass, to a coral reef.

1. Collect water samples at three points along a transect that extends from a windward mangrove stand, across a seagrass bed, to patch reefs. Take all samples from a depth of

0.5 m. Label bottles and store in cool box for analysis during the evening lab. Measure temperature at 0.5 m at each site.

Site 3 Temperature pH Salinity Dissolved O 2 Nitrates Phosphates Turbidity

Site 1

Site 2

Describe each site (e.g., depth, turbidity, SAVs, wave energy, etc.):

Site 1: __________________________________________________________________________ Site 2: __________________________________________________________________________ Site 3: __________________________________________________________________________

As you move along the transect, count the number of Cassiopea that you observe. Discuss reasons why the mangrove community is the “preferred” habitat of this animal.

Field Activity: Diversity of Macrofauna in Mangrove, Seagrass, and Coral-Reef Communities

Objective: Participants will compare the obvious complexity of coral macrofaunal

communities with seagrass and subtidal mangrove communities

Summary: Participants will snorkel along transects from the mangroves across seagrass beds to the extensive patch reefs around the cays. Each participant will make an inventory of the species observed an attempt to compare diversity and dominant species in each community.

Materials: Clipboard, data sheets, pencil Field guides Collecting bags Marking pen Cool box Snorkel gear

Procedure: Break the large group into three smaller groups of equal size. Each small group will spend approximately 45 minutes at each of three stations.

Complete the following tables and compare mangrove, seagrass, and patch-reef communities for species richness and abundance of organisms. Collect samples of macroalgae and seagrass from the mangrove, seagrass, and patch-reef sites for detailed microscopic examination in the laboratory.

Station 1. Mangrove community. Station 2. Seagrass community. Station 3. Coral-reef community.

1. List fishes, invertebrates, corals, and algae observed in each of the communities:

Mangrove

Seagrass

Patch Reef 1.

Fishes 4.

Inverte-brates 4.

Corals 4.

2. Rank the three most commonly observed species for each community type: Community Species Group

Rank

Type

1 2 3 Mangrove

Fishes Corals Invertebrates Algae

Seagrass Fishes Corals Invertebrates Algae

Patch reef Fishes Corals Invertebrates Algae

Field Activity: Larvae Transport from Fish Spawning Aggregation Sites

Objective: Participants will conduct drift studies to determine the probable planktonic pathway between fish spawning aggregation sites, and inshore mangrove envi- ronments.

Summary: Participants will utilize simple current drogues and handheld GPS systems to map the transport pathways and speeds of currents as they move away from known spawning aggregation sites east of Calabash Caye and Blackbird Caye.

Materials: Clipboard, data sheets, and pencil Current drogues Handheld Garmin GPS Nautical Charts Handheld calculator

Procedures: Participants will be divided into 3 groups and rotate through each of 3 stations.

1. Participants will learn the basic functions of a handheld Garmin 12 GPS unit.

2. Participants will use nautical charts to learn how to plot positions.

3. Participants will conduct field studies from an outboard skiff, using current drogues and a handheld GPS to calculate the speed and direction of surface currents at spawning aggregation sites. Finally, participants will plot the data, gathered in the field, on the nautical charts, and hypothesize about transport velocities and routes.

Station 1: Nautical Charts

1. Using the nautical charts provided, determine north, the scale of the map (note that one minute of latitude is equal to 60 nautical miles). What are the two coordinate systems? What is the position of Calabash Caye (using Latitude and Longitude with degrees, minutes, and seconds)?

2. What is Universal Transverse Mercator? What are its advantages and disadvantages?

3. What is the water depth between Turneffe Atoll and Lighthouse Reef Atoll? What is the depth within the Turneffe? What is the depth east of Lighthouse Reef Atoll?

4. Map two spawning aggregation sites on the nautical chart – Blackbird Caye, and Cala- bash Caye:

Station 2: Handheld Garmin GPS

1. Participants will familiarize themselves with the various menus on the GPS. Please be sure that the datum is set at NAD 27 Central, the units are metric, the coordinate system to Lat Long (degrees, minutes, seconds) and be sure that the language is English.

2. Compare the satellite reception standing on the open beach versus that under shade of dense trees or inside a building. What is the maximum accuracy that you can attain?

3. Learn how to mark a waypoint. Record the number (name), time, and location of the waypoint. Repeat this process at a different location (at least 50 meters away from the first).

4. Use the Distance Function to calculate the bearing and distance using a simple map with a north arrow, scale bar and vector indicating the relationship between the two points. Rough- ly map the relationship between these two points below or on a separate sheet.

Station 3: Field Observations of Surface Currents Using Drogues.

1. Participants should familiarize themselves with the use of the current drogues before heading into the field.

2. Do fish larvae float or sink after spawning? Why? Are currents consistent at all water depths? Which currents are transporting larvae, those currents at the surface, or those at 30 m depth?

3. Using the GPS as a compass, or the compass on the boat, estimate the speed and direction of the wind. Be sure to use the appropriate convention - state which direction the wind is coming from.

4. Using a current drogue, measure the speed and direction of the currents at the spawning site – Calabash Caye or Blackbird Caye. Do this by installing the drogue in the water at the spawn site and leaving for several minutes so that the drogue can begin to move with the current. Take a GPS position (be sure to note down the number in your notebook) to mark the position of installation. Let the drogue drift with the prevailing current and take position every 15 minutes or so, allowing the drogue to drift as long as possible, given the available time. Repeat the process several times as time allows.

4. Back in the laboratory, record your data on the overall data sheet being collected by the entire class. Plot the speed and direction of the currents from your data as a vector, with the length of the vector indicating the speed, and the direction of the vector consistent with that bearing obtained using the distance function on the GPS. Note that you will have to calculate the speed from the formula: Rate = Distance x Time. Current speeds are reported in cm/second so you will have to make appropriate conversions. You will obtain the starting and stopping time for the vector from the start and stop positions in the GPS, and subtract to obtain the number of minutes. The Distance and Bearing between the starting and stopping points will be evaluated using the distance function on the GPS. All of the data for the class should be plotted on a single graphic to indicate the variation in the speed and direction of the currents at the spawning site.

Field Activity: The Value of Mangrove Swamps as Nurseries

Objective: Participants will learn to appreciate the role of mangroves as nurseries for many commercial and sports fishes in Belize.

Summary: Participants will examine the waters among mangrove prop roots for immature stages of larger fish and invertebrates. They will examine adjacent systems to locate these same species. To appreciate how the flow of energy from the swamps helps to support adjacent communities, they will examine the composition and export of leaf litter from the mangrove.

Materials: Clipboard, data sheets, pencil Snorkel gear

Field guides Quadrat frames Collecting bags Specimen trays Plankton net

Procedures: Break the large group into three smaller groups. Each group will spend approximately 45 minutes at each of three stations in the mangrove channel,

a reef area, and in the mangrove forest. Participants will look for sizes and abundances in fishes in the various habitats.

Station 1. Mangrove as a nursery. At this site, you will swim along a mangrove channel to look for juvenile fish and invertebrate species in the water column. Compare the number and size of individuals of the same species with those living in the adjacent reef system.

1. Swim a 50 m transect along the mangrove channel, looking carefully for juvenile fish and invertebrates.

2. List species of fish that you see and the number of each of these species, along with the approximate mean size for these fish. If you can't identify to the species level, family level or common names are OK.

Fish species

# of fish

Mean Length (mm)

Food preference

3. As you are swimming, look for tiny invertebrates in the water column along the roots. Do you see any mysids, copepods, or shrimp? Are they under closed canopy or in light gaps? What do they eat? Which organisms prey on these?

4. Collect a plankton-tow sample of water near the roots. How does the density of organisms in this sample compare with the reef sample?

5. Look at the bottom. Do you see any leaf litter? What species of mangrove is most common? Are the leaves intact or broken? Describe the leaves found on the bottom.

Station 2. Fish populations in reef communities. At this site, you will swim around a reef area to look for the juvenile fish and invertebrates.

1. Swim a 50 m transect across a patch-reef area. Count and visually estimate the lengths of all the fish that you see and record these in the table below, along with their food preferences.

Fish species

# of fish

Mean Length (mm)

Food preference

2. As you are swimming look for tiny invertebrates in the water column. How does this compare with the mangrove community of water-column invertebrates?

3. Collect a plankton-tow sample. How does the density of organisms in this sample compare with the mangrove sample?

4. Look on the bottom for red-mangrove leaf litter. Can you find any recognizable leaves?

Field Activity: Hurricane Hattie Damage at Soldier Cay

Objective: Participants will survey a small mangrove island of known damage by a major hurricane to determine how this island has changed following the storm.

Summary: Participants will examine the flora and the physical and vegetative structure of Soldier Cay. They will compare the current status of the island with accounts made in 1960 (pre-Hurricane Hattie) and in 1962 (post-Hurricane Hattie).

Materials: Clipboard, data sheets, pencil Collecting bags Specimen trays Measuring tapes Corer Clinometer Telescoping rod Compass Field guide to Caribbean plants

Procedure: The large group will be broken up into three smaller groups of equal size. Each small group will spend approximately 45 minutes at each of the three stations.

Station 1. The effects of Hurricane Hattie on human habitation and activities at Soldier Cay.

At this station, you will explore Soldier Cay and look for evidence of human habitation and activities that existed there before 1961. (Note: Refer to the text and maps in Stoddart (1962, 1965) publications, included in the appendix of the Mangrove Ecology Field Manual, for descriptions of the island in 1960 and 1962.)

As a reference point; try to find the location of the “house posts” indicated on the 1962 map. Prior to 1961, the central portion of the island was a coconut plantation. Look for evidence of

coconut cultivation. Examine and describe the substrate of the vegetated portion of Soldier Cay at three intervals

along an east-to-west transect:

Site 1 (Leeward)

Site 2 (Middle)

Site 3 (Windward)

Based on your observations, is this island presently suitable for cultivation?

Station 2. The effects of Hurricane Hattie on the physiography of Soldier Cay. At this station, you will examine the current physiography of Soldier Cay and compare it to maps made in 1960 (pre-Hurricane Hattie) and in 1962 (post-Hurricane Hattie) by D. R. Stoddart.

Measure the current size of Soldier Cay. (Note: In 1960, it was 145 yards long with a maximum width of 55 yards.)

Maximum length Maximum width Maximum elevation

On the east side of the island beginning near the north end and extending southward, examine the platform on which Soldier Cay stands. Describe the intertidal and subtidal areas that immediately border the seaward side of the cay, including the rock pavement; detached loose boulders, and tidal elevation.

What is the origin of the substrate in this area? How did the large blocks of rubble get in their current positions? At the landward edge of the platform, locate the storm or “shingle” ridge. Examine the

composition of the rubble in the ridge. Why is this called a shingle ridge? Has more than one ridge formed? If so, what does this indicate?

Station 3. Changes in the vegetation of Soldier Cay since Hurricane Hattie. At this station, you will examine the flora and vegetative structure of Soldier Cay and compare its current status with floristic surveys made in 1960 (pre-Hurricane Hattie) and in 1962 (post- Hurricane Hattie) by D.R Stoddart.

Walk a transect across Soldier Cay. Measure the height of the vegetation at 10 m intervals along a transect across the island. Record the number of strata in the canopy and the plant species where height measurements are made. Use Stoddart's 1962 map of Soldier Cay to mark the location and direction of the transect.

Vegetation Interval

Species height

Number of strata

Examine each plant species encountered along the transect. List the species. If you find a plant that you do not know, collect a small sample of it. If possible, collect a portion with flowers.

11.

12.

13.

14.

15.

16.

17.

18.

19.

10.

20.

Look for remains of fallen trees. Record the species, location, and direction of any tree fall that you find.

Mean pulsation rate = ______ (Control)